Polysaccharide, unknown

A 3-deoxyheptulosaric acid has been found in the LPS from Acineto-bacter calcoaceticus NCTC 10305. Another acid of this class, 3-deoxy-o-/yxo-heptulosaric acid ° (30), is a component of a plant polysaccharide. One 4-deoxyhexulosonic acid, of unknown configuration, is known and is a component of the E. coli K3 capsular polysaccharide. "... 

The content by weight of carbohydrate in glycoproteins may vary from only a few percent to over 50 percent in some proteins in mucous secretions. Although the function of the polysaccharide in most glycoproteins is unknown, in some cases it may provide hydrophilicity, recognition, and points of noncovalent interaction with other proteins through lectin-like affinity binding. 

Yeasts may be identified, and classified, according to the H-l portion of the p.m.r. spectrum of the cell-wall, D-mannose-containing polysaccharide. This portion has served most frequently as a fingerprint for identification of unknown yeasts, but, sometimes, the presence of certain signals of a particular chemical-shift could indicate the presence of certain structures (for example, /3-D-linkages).121 For some... 

The structure of mannose-rich polysaccharide core in GL4 is close to that of yeast mannan (from Saccharomyces cerevisiae), which was inactive for IL-6 induction in a human peripheral whole-blood cells test system. This fact suggests that not the mannose moieties but other components, such as the lipophilic moiety and/or phosphates, are important for the activity. The lipophilic products in HF-hydrolysate of GL4 were then analyzed. In addition to peaks corresponding to the known fatty acids (C16 0, C18 1), two other unknown ion peaks at m/z 330 and 356 were found by FAB-MS (data not shown). 

Steigmann A (1964) Microconstituents of photographic gelatin. Desoxyribonucleic acid and an unknown polysaccharide. Sci Ind Phot 35, 145-157. 

The fungus produces a (l-galactosidase, a rhamogalacturonan lyase, an acetylesterase, and perhaps two other proteins of unknown type that convert the polysaccharide into the toxic product. Lepidimoide has been reported to be phytotoxic to a variety of plants, but may also promote the growth of the plants in which it is produced. 

The function of the sulfate residue in these polysaccharides is unknown but the suggestion has been made that just as starch is synthesised from D-glucose 1-phosphate by the action of phosphorylase, so the seaweed polysaccharides are formed from the appropriate sugar sulfate by reaction with a sulfatase. ... 

Structural Analysis of a Polysaccharide A polysaccharide of unknown structure was isolated, subjected to exhaustive methylation, and hydrolyzed. Analysis of the products revealed three methylated sugars in the ratio 20 1 1. The sugars were 2,3,4-tri-O-methyl-D-glucose 2,4-di-O-methyl-D-glucose and 2,3,4,6-tetra-O-methyl-D-glucose. What is the structure of the polysaccharide ... 

Three monosaccharides of the group were identified which contain an amino group at both C-2 and C-3. These include acylated 2,3-diamino-2,3-dideoxy-D-glucose, which is a component of the lipid A region of lipopoly-saccharides from Rhodopseudomonas,144 and 2,3-di(acetamido)-2,3-dideoxy-D-glucuronic145 and -D-mannuronic146 acids, identified as constituents of P. aeruginosa O-specific polysaccharides. The pathway of their biosynthesis, and their activated forms, remain unknown. 

It is necessary to postulate the existence of a previously unknown, modification reaction of glycosyl nucleotides, that is, deoxygenation at C-4, in order to explain the formation of 4-deoxy-D-arafc//io-hexose, a monosaccharide constituent of Citrobacter lipopolysaccharide.202 4-Deoxy-L-threo-hex-4-enuronic acid, found in Klebsiella K22 polysaccharide,203 may be formed through dehydration of the D-galacturonic acid group or residue, either in the glycosyl nucleotide, or in the polysaccharide. 

Due to the limitations of the TBA assays (8), it has not been possible, on this basis, to define more clearly the constitution of the KDO trisaccharide. On the other hand, detailed spectroscopic analyses of the KDO region of LPS have not been reported. In fact, the anomeric configurations of the KDO residues in LPS are still unknown, whereas such configurations have been assigned to the KDO residues present in a number of capsular polysaccharides (9, 3, 2J ) (cf. the chapter by Jann in this volume). 

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